Buns of Steel: The Story of a Cheeseburger Shaped BattleBot

Have you ever hit on an idea so good the whole room bursts into laughter? Enter the cheeseburger bot …

Our BattleBots group Poor Life Choices was born of a desire to build something the world had never seen. Half the team was harboring childhood dreams of building for BattleBots, the other half was just crazy enough to try to build a combat cheeseburger for the fun of it.

Once we settled on the basic burger design we had five weeks to move from first draft to finished robot. As a first-year team thrown into a field of seasoned, multi-decade veterans, we knew we had tremendous challenges to overcome. Mistakes were made and friendships were tested. A lot of late night coffees and burgers were consumed. Many favors were asked.

A FAB TEAM

From the start Miles Pekala worked furiously to CAD up the burger components into plans that could be shared with our small groups — all Power Racing Series alums — in three cities: Oakland, Baltimore, and Chicago. In Oakland, I led the workshop at NIMBY Space where Jordan Bunker and Lindsay Oliver joined in fabrication and logistics. This group worked as the core of creation and assembly, with frequent field trips to local metal suppliers and hackerspaces.

Our teammates Charles Wittington, Brice Farrell, Jeremy Ashinghurst, and Angela Rothbaum were back east and connected by Baltimore Hackerspace. This group consulted on and machined the parts for the weapon system and kept an eye on the overall budget, asking favors at The Foundery for machining aluminum components and seeking sources of funding at every level. Of all the roles you can have on a build, team accountant is often the unsung hero.

CHALLENGES

One of the major fabrication issues was creating and aligning the pieces for the interior tube frame. Twenty-foot sections of .75″ OD (outer diameter) A513 tube steel were acquired, cut, and carried over to industrial art space M0xy and its Department of Spontaneous Combustion, where a very old and suspiciously safety-less tube roller lives in the back of the metal shop. With no emergency stop or user protection at all, we named this contraption “Bendytube Crushyourthumbs.”

This tool didn’t have the appropriate dies for the patty, which was created from 2″ OD structural tube steel. For that we had to ask for a favor from Zach Wetzel at his workshop in Richmond, California.

Back at NIMBY we needed welding fixtures for nearly every joint type. Precision was crucial for notching and aligning a few hundred feet of carefully bent tube. Jordan and I worked at this for many sleepless nights, salvaging wood and MDF and creating CAD and CAM files to cut the fixtures on a little Shapeoko CNC.

The toughest obstacle on the entire robot came from needing to run the two systems — drive and weapon — on one battery. The drive is running two brushed DC motors, MY1020 style, the kind you’d buy for electric scooters. The weapon is run on a brushless RC airplane motor, the Toro Beast. We couldn’t have integrated these to run on the same 10s LiPo battery without the help of our friends.

BRINGING HOME THE BACON

We needed a bacon blade, and Advanced Metalcraft in Chicago has a laser cutter powerful enough for hardened steel. Luckily, our honorary teammate, Jakub Klimuszko, a member of Chicago’s Pumping Station: One makerspace (which was founded by teammates Jordan Bunker and Jim Burke), is an accomplished welder and fabricator working for Advanced Metalcraft. He lobbied his boss Peter Anwar and the company agreed to sponsor us with a very generous donation of materials. Jakub then donated over 100 hours of his own time to brake-bend and weld-up the buns of steel!

Despite the time crunch, a great amount of research went into bearings, shafts, and couplers to get the bacon swinging. Due to the shape of the armor, getting the weapon and drive to fit together and work together without interference was a real challenge. The clearance between the three motors was so tight that we had to shave down the bolts on the drive motors to get the weapon in. We were definitely living dangerously as we approached the deadline!

COMPLICATIONS

Of course, there were unexpected hiccups. Fitting the gorgeous armor to the tube frame we realized that the frame was curved on a radius that matched the armor version one, but what we’d sent out in CAD and received back in steel was armor version two. Whoops. Hacking happened.

We were also missing some key parts when we hit the road: The vendor we purchased the 10s LiPo batteries from delayed shipping so long that they didn’t show up in Oakland until after we had left for Long Beach to film. We had to find emergency LiPos that would fit in the space allotted under the motors, and we had to make do with 8s LiPos. The day we arrived back home the correct batteries were waiting by the door, taunting us.

HOORAY FOR HELP

When we began the project we had no sponsorship at all. By a few strokes of excellent fortune, friends at DigiKey and Imgur received word of our crazy little burger robot and contributed crucial funds to the build. A local burger joint in San Francisco, WesBurger, also joined in. We really couldn’t have gone the distance without this help!

Despite the challenges, the time, and the complications, we got that burger to the arena! 10/10 would build again. As I write this new episodes are airing weekly on Discovery Channel and, having seen all those robots up close, I have to say you’re
in for a great season.